PARAMETRIC WAVE-BREAKING ON STEEP REEFS

Shih-Feng Su, Alex Sheremet, Jane McKee Smith

Abstract

A numerical model based on a nonlinear mild-slope equation, and modified to account for wave dissipation due to breaking is applied to investigate the transformation of the wave spectrum over a fringing reef. The three parameters (γ, B, F) of the breaking model are calibrated for the best fit between the spectral shapes observed and modeled using an inverse modeling approach. The relationship between optimal values for γ and B derived from numerical simulations and other parameters characterizing wave and slope conditions (e.g., deep-water wave steepness, wave dispersivity, nonlinearity parameter) are investigated with the goal of formulating guidelines for the selection of adequate values. The results of this study disagree significantly with previously-proposed empirical relations between γ and the deep-water wave steepness, but show good agreement with empirical relations relating γ to other parameters. The breaking intensity parameter B shows a largely linear dependency on the nonlinearity parameter.